Contaminant remediation, biodegradation and volatilization methods and apparatuses

ABSTRACT

Methods and apparatuses for removing contaminants. At least one injection well is drilled through the vadose zone to a depth below the water table defining the upper boundary of the aquifer. A plurality of venting wells or venting laterals are established to a depth above the water table sufficient to discourage fouling by contaminated water or condensate, and oxygenated substances are injected under pressure through the injection wells. Additional biochemical cleansing may occur at ground level prior to venting of contaminated air. Microbes natural to the contaminated site may be extracted, analyzed, fermented, and reintroduced to enhance biodegradation, and nutrients, food, or both, may be supplied to the microbial population to sustain high levels of degradation activity. Relatively pure liquid contaminant may be separated from other fluids, such as water. Modes of enhancing the lateral dispersion of injected substances are disclosed, for example, hingedly connected radially extendible injection tubes which expand the radius of injection.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional application from U.S. patentapplication Ser. No. 08/179,584 to Jeffery F. Billings, et al., filed onJan. 10, 1994 (issuing as U.S. Pat. No. 5,472,294 on Dec. 5, 1995),which is a continuation-in-part application of U.S. patent applicationSer. No. 07/800,545 to Jeffery F. Billings and Gale K. Billings, filedon Nov. 27, 1991 (issued as U.S. Pat. No. 5,277,518), entitledContaminant Remediation, Biodegradation and Removal Methods andApparatuses, which is a continuation-in-part application of U.S. patentapplication Ser. No. 07/712,919, entitled Subsurface Remediation,Biodegradation and Extraction Methods and Apparatuses, to Jeffery F.Billings and Gale K. Billings, filed on Jun. 7, 1991 (issued as U.S.Pat. No. 5,221,159) which is a continuation-in-part application of U.S.patent application Ser. No. 07/500,767, entitled SubsurfaceVolatilization Method and System, to Jeffery F. Billings, filed on Mar.28, 1990, now abandoned, the teachings all of which are incorporatedherein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention (Technical Field)

The present invention relates generally to methods and apparatuses forin situ remediation of organic contaminants, such as hydrocarbons, andinorganic contaminants, such as metals, from subsurface soil and groundwater. In situ remediation of excavated materials and surface spills ofliquid contaminants also may be conducted utilizing the presentinvention.

2. Background Art

The background of the present inventions is discussed in depth in U.S.patent application Ser. No. 07/712,919, entitled Subsurface Remediation,Biodegradation and Extraction Methods and Apparatuses, to Jeffery F.Billings and Gale K. Billings, filed on Jun. 7, 1991, and in U.S. patentapplication Ser. No. 07/500,767, entitled Subsurface VolatilizationMethod and System, to Jeffery F. Billings, filed on Mar. 28, 1990, nowabandoned, the teachings of both of which are incorporated herein byreference.

The vacuum extraction inventions disclosed in the above two applications(and all known vacuum extraction systems) have, due to the use ofextraction wells having perforations near the bottom thereof,encountered problems with the upwelling or condensation of contaminatedsubsurface water into the extraction wells, and concomitant fouling ofthe extraction wells and pumps, thus necessitating expensive surfacewater treatment equipment. The present invention solves this problem ina number of ways, while enhancing remediation.

Additionally, as disclosed herein, the liquid contaminant extractionapparatus and method of U.S. patent application Ser. No. 07/712,919 maybe employed to remove contaminants from surface waters, such as lakes,rivers, seas, and oceans.

Furthermore, as disclosed herein, the volatilization inventionsemploying injection wells disclosed in U.S. applications Ser. Nos.07/712,919 and 07/500,767 may be used with or without extraction wells.

SUMMARY OF THE INVENTION (DISCLOSURE OF THE INVENTION)

The present invention comprises in situ methods and apparatuses forremoval of contaminants from soil or from ground water, or both.

The first method and apparatus comprises establishing in situ at leastone venting well having gas-permeable openings at an upper portionthereof, whereby volatile contaminants in the ground water or soil areremoved through the venting well. In the preferred embodiment, at leastone injection well is established in situ and an oxygen-containingsubstance, such as a gas or fluid, is injected into the injection well.Optionally, a vacuum is applied to the venting well. Preferably, theventing well and the injection well are within two hundred feet of oneanother and make up a well nest. The injection well, depending on sitestratigraphy, is preferably within ten feet of the venting well and maybe adjacent the venting well within a same bore hole. Preferably, theoxygen-containing gas is heated by solar heating, the venting wellcomprises a condensate drain at a lower end thereof, and microorganismsand nutrients, food, or both, are provided to a subsurface contaminatedzone. The invention may additionally comprise sampling soil or water,isolating at least one microorganism useful in biodegrading thecontaminants, fermenting the isolated microorganisms to increase theirpopulation, and inserting the fermented microorganisms into thesubsurface. The invention may also comprise providing an elongated tubereservoir capped at one end (preferably to the bore hole of a ventingwell, an injection well, or both), providing entry ports in theelongated tube reservoir, surrounding the entry ports with filtrationmeans, and collecting contaminants in the elongated tube reservoir bypassage thereof through the filtration means. The invention may furthercomprise impregnating water with microorganisms useful in biodegradationof the contaminant, confining the impregnated water to one or morecontainers, and bubbling contaminants from the venting well through theimpregnated water within the containers. Preferably, the venting welladditionally comprises gas-permeable but low capillary-lift fillmaterial below the gas-permeable openings in the venting well.

The second method and apparatus of the invention comprises: establishingin situ a venting lateral comprising gas-permeable openings therein;establishing in situ a plurality of injection wells; and injectingoxygen-containing gas or other substance into the injection wells;whereby volatile contaminants in the ground water or soil are removedthrough the venting lateral. Optionally, a vacuum is applied to theventing lateral. Preferably, the venting lateral and the injection wellare within two hundred feet of one another and make up a well nest, theoxygen-containing gas or other substance is heated by solar heating, andmicroorganisms and nutrients, food, or both, are provided to thesubsurface. The invention may additionally comprise sampling soil orwater, isolating at least one microorganism useful in biodegrading thecontaminants, fermenting the isolated microorganisms to increase theirpopulation, and inserting the fermented microorganisms into thesubsurface. The invention may also comprise providing an elongated tubereservoir capped at one end (preferably to an injection well), providingentry ports in the elongated tube reservoir, surrounding the entry portswith filtration means, and collecting contaminants in the elongated tubereservoir by passage thereof through the filtration means. The inventionmay further comprise impregnating water with microorganisms useful inbiodegradation of the contaminant, confining the impregnated water toone or more containers, and bubbling contaminants from the venting wellthrough the impregnated water within the containers. Preferably, theventing well additionally comprises one or more vertical vents beneaththe gas-permeable openings of the venting lateral. The vertical vent maybe a gas-permeable chimney of sand or a venting well havinggas-permeable openings therein and, optionally, being fluidly connectedto the venting lateral, or a combination of the two types (a ventingwell extending partially down a sand chimney).

The third method and apparatus of the invention comprises: establishingin situ a venting lateral comprising gas-permeable openings therein; andplacing a vertical vent beneath the venting lateral; whereby volatilecontaminants in the ground water or soil are removed through the ventinglateral. In the preferred embodiment, at least one injection well isestablished in situ and oxygen-containing substance, such as a gas, isinjected into the injection well. Optionally, a vacuum is applied to theventing lateral. Preferably, the venting lateral and the injection wellare within two hundred feet of one another and make up a well nest, theoxygen-containing gas is heated by solar heating, and microorganisms andnutrients, food, or both, are provided to the subsurface. The inventionmay additionally comprise sampling soil or water, isolating at least onemicroorganism useful in biodegrading the contaminants, fermenting theisolated microorganisms to increase their population, and inserting thefermented microorganisms into the subsurface. The invention may alsocomprise providing an elongated tube reservoir capped at one end(preferably to an injection well), providing entry ports in theelongated tube reservoir, surrounding the entry ports with filtrationmeans, and collecting contaminants in the elongated tube reservoir bypassage thereof through the filtration means. The invention may furthercomprise impregnating water with microorganisms useful in biodegradationof the contaminant, confining the impregnated water to one or morecontainers, and bubbling contaminants from the venting well through theimpregnated water within the containers. Preferably, the vertical ventis beneath the gas-permeable opening of the venting lateral. Thevertical vent may be a gas-permeable chimney of sand or a venting wellhaving gas-permeable openings therein and, optionally, being fluidlyconnected to the venting lateral, or a combination of the two types (aventing well extending partially down a sand chimney).

The fourth method and apparatus of the invention comprises: establishingin situ at least one injection well into the ground water; injectingoxygen-containing substance, such as a gas, into the injection well tovolatilize and biodegrade contaminants in the ground water and soil; andpermitting upward migration of the volatilized and biodegradedcontaminants without one or more venting conduits. In other words, noventing wells, venting laterals, or equivalent equipment is used.Preferably, the oxygen-containing gas is heated by solar heating andmicroorganisms and nutrients, food, or both, are provided to thesubsurface. The invention may additionally comprise sampling water orsoil, isolating at least one microorganism useful in biodegrading thecontaminants, fermenting the isolated microorganisms to increase theirpopulation, and inserting the fermented microorganisms into thesubsurface. The invention may also comprise providing an elongated tubereservoir capped at one end (preferably to an injection well), providingentry ports in the elongated tube reservoir, surrounding the entry portswith filtration means, and collecting contaminants in the elongated tubereservoir by passage thereof through the filtration means.

The invention optionally may comprise the use of an expander apparatuswhich permits lateral injection of substances radially outward from thewell bore. One or more hollow radial injection tubes may be connected toa source of injected substances, placed down-well in a verticaldisposition, and then pivoted through a vertical angle radially outwardfrom the well. The pivoting of the radial injection tubes gives them avariable degree of horizontal disposition, so that substances may beforced through them radially outward from the well to enhance injectionefficiency.

In all embodiments, the rate of biodegradation is controllable byvarying the oxygen available to the biodegrading organisms. Bydeliberately manipulating the available oxygen, the user is able toincrease or suppress the rate of bio-organism reproduction andmetabolism, with a corresponding effect upon the rate of biodegradationof contaminants.

Accordingly, a primary object and purpose of the present invention is toprovide an improved method and associated system for removingcontaminants which does not suffer from the deleterious effects ofupwelling and condensation of contaminated liquid water.

Another object of the present invention is to remove contaminants from asubsurface aquifer and from surface water, the contaminants beingremoved in relatively pure form.

An additional object of the present invention is to provide a method andsystem of removal of contaminants from subsurface soil as well as fromground water.

Another object and purpose of the present invention is to provide arelatively inexpensive method and system for in situ removal ofcontaminants from subsurface ground water and soil, as well as fromsurface waters.

A primary advantage of the present invention is that it is relativelyinexpensive, efficient, and quick because of the combination oftechnologies employed.

An additional advantage of the present invention is that it integratessimultaneous remediation of free-product, soil residual, vapors, andcontaminated ground water. If the invention is operated in thesubsurface, these processes take place in: (a) the vadose zone; (b) thecapillary fringe zone between the vadose zone and the water table; (c)at the water table; and (d) below the water table, synchronously. Itdoes so by synchronous attack upon each of the physical and chemicalcharacteristics of the four types of contamination. The invention isalso operable above ground, for example, on excavated materials.

Yet another advantage of the present invention is that contaminated airmay either be vented or treated before venting.

An additional advantage of the present invention is that liquidhydrocarbon contaminant may be removed from contaminated water such thatthe hydrocarbon contaminant is pure enough to be refined rather thanhandled as a toxic waste.

Other objects, advantages, and novel features, and further scope ofapplicability of the present invention will be set forth in part in thedetailed description to follow, taken in conjunction with theaccompanying drawings, and in part will become apparent to those skilledin the art upon examination of the following, or may be learned bypractice of the invention. The objects and advantages of the inventionmay be realized and attained by means of the instrumentalities andcombinations particularly pointed out in the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated into and form a partof the specification, illustrate several embodiments of the presentinvention and, together with the description, serve to explain theprinciples of the invention. The drawings are only for the purpose ofillustrating a preferred embodiment of the invention and are not to beconstrued as limiting the invention.

FIG. 1 is a schematic illustration in cross-section of a subterraneansoil formation having a water table, and wherein the method and systemof the present invention are being applied;

FIG. 2 is a plan view of an array of wells connected to a singlecompressor/vacuum pump station;

FIG. 3 is a schematic illustration in cross-section of a subterraneansoil formation having a water table, wherein the preferred method andsystem of the present invention are being applied;

FIG. 4 is a schematic illustration in cross-section of a subterraneansoil formation having a water table, and wherein an alternative methodand system of the present invention are being applied;

FIG. 5 is an exterior view of the free-product extraction apparatus ofthe invention;

FIG. 6 is an interior exposed view of the free-product extractionapparatus;

FIG. 7 is a further interior exposed view of the free-product extractionapparatus;

FIG. 8 is an exterior view of the biotreater apparatus of the invention;

FIG. 9 is an interior exposed view of the biotreater apparatus;

FIG. 10 is an illustration of interbasal components of the biotreaterapparatus;

FIG. 11 is an illustration of a portion of the FIG. 3 embodiment,showing the optional injection radius extension elements of theinvention;

FIG. 12 is an enlarged view of a portion of the FIG. 11 embodiment,showing the injection radius extension elements in a collapsed position;and

FIG. 13 is an additional view of the FIG. 12 embodiment, showing theinjection radius extension elements in an extended position;

FIG. 14 is a top view of the embodiment of FIG. 13; and

FIG. 15 illustrates an alternative embodiment of the embodiment of FIG.13.

DESCRIPTION OF THE PREFERRED EMBODIMENTS (BEST MODES FOR CARRYING OUTTHE INVENTION)

The present invention relates to methods and apparatuses forremediating, biodegrading, and extracting organic and inorganiccontaminants.

The air-injection methods and apparatuses of the present invention arepreferably employed to remove contaminants from subsurface soil andground water by physical, chemical, and biological means, in situ.However, the same methods and apparatuses may be employed in man-madelandfills, with excavated soils, to directly treat industrial wastes,and the like. The air-injection/air-venting systems of the invention maybe combined with bio-treatment of contaminated gases prior to venting,extraction of contaminants from water, injection ofcontaminant-consuming microbes into the contaminants, and growthstimulation of natural or injected microbes by subsurface injection ofnutrients (predominantly inorganic compounds), food (predominantlyorganic compounds), or both.

The liquid contaminant extraction method and apparatus of the inventionis preferably used to remove free liquid contaminants from subsurfacewater. However, the invention may also be used to remove liquidcontaminants from surface waters. For example, the invention may be usedto assist in remediation of hydrocarbon spills (e.g., from an oil tankerspill) so as to recover contaminants which are thereafter relativelypure and therefore commercially useful.

Referring to FIGS. 1 and 3, the preferred embodiment of the presentair-injection invention is illustrated therein as directed to theremediation of a contaminated site 10, wherein there is a vadose zone 12overlying a ground water reservoir or aquifer 14. The contamination willbe present in the ground water reservoir or aquifer 14 and in the vadosezone 12. The upper boundary of the aquifer 14 is defined by the level ofthe water table 16. It will be recognized that there may be a capillaryzone (not shown separately) above the water table 16, in which water isdrawn upwardly into the vadose zone 12 by capillary action, and the term"vadose zone" is intended to cover this capillary zone. In general, thecapillary zone will be contaminated if the ground water itself iscontaminated.

In the preferred embodiment, a plurality of injection wells 18 extendfrom the ground surface 20 to a level beneath the water table 16 intothe aquifer 14. The injection wells 18 are connected to an aircompressor 22 via manifold 102. The air compressor 22 preferably has acapacity of at least approximately 10 to 300 cubic feet per minute (cfm)at 1 to 100 pounds per square inch (psi). Air or other oxygen-containinggas or fluid is introduced into the injection well 18 via the aircompressor 22. The term "air," as used throughout the specification, isintended to include oxygen-containing gases.

Other oxygen-containing substances besides air or otheroxygen-containing gases may alternatively be employed in the successfulpracticing of the invention. The bioremediation aspect of the inventionincludes the introduction of substances into the subsurface to augmentthe oxygen available for microbial metabolism. Oxygen-containing fluids,including liquids, may be used. Non-limiting examples ofoxygen-containing fluids useable in the invention are liquid peroxides(e.g., hydrogen peroxide) and aqueous or other solutions of nitrate orsulfate compounds. Similarly, solid substances or mixtures of substanceswhich contain biochemically available oxygen (perhaps after dissolutionin water) may be introduced directly into an injection well 18. Forexample, solids (generally powdered) such as NO_(x) and/or SO_(x)compounds (e.g., nitrates and sulfates), or various peroxides which aresolid at standard conditions of temperature or pressure (e.g., calciumperoxide) may be introduced into injection wells 18 to augment availableoxygen.

The injection wells 18 are preferably made of common materials such aspolyvinyl chloride (PVC). Injection wells are completed and emplacedusing common well methodology. The injection wells 18 preferably includea gas-impermeable well liner 24, such as a PVC pipe, along the majorpart of its length. The injection well 18 extends to a depth ofpreferably one to 100 feet beneath the water table 16. The depth ofpenetration below the water table 16 depends on the thickness or extentof the contaminated portion of the ground water aquifer 14. Air, orother oxygen-containing substance, is introduced into the injection well18 and exits the injection well 18 through a screen 26 or otherperforated material, of a common manufactured type, into the aquifer 14at the chosen depth.

The end of the injection well 18 in the aquifer 14 contains openings,such as from a gravel-packed, 10-40 slot screen 26 or piping with holesor perforations. The screen 26 functions as a sparger to introducepressurized air into the aquifer 14, so as to stimulate circulation ofthe water and mixture of the air and water. Injection is accomplished atlow to moderate air pressures.

Venting wells 28 are located in the vadose zone 12 within apredetermined distance from an injection well 18. The relative distancein both the horizontal and vertical dimensions between injection wells18 and venting wells 28 is critical to proper operation of the presentsystem. These distances are chosen based on site characteristics. This"well nesting" is discussed in detail in the '919 application. There maybe "nests" having a plurality of extraction wells for each injectionwell, a plurality of injection wells for each extraction well, or pairsof injection/extraction wells (from 200 feet apart to within the sameboreholes). A venting well 28 includes a gas-impermeable pipe 30 alongthe major portion of its length, with a space between the pipe 30 andthe well hole. The upper end of venting well 28 contains perforations oropenings 32, such as a sparger from a gravel packed, 10-40 slot aperturesize well screen or piping with holes in it. The lower portion ofventing well 28 comprises fill material 110 packed around pipe 30. Fillmaterial 110 is preferably relatively permeable to air and other gasesyet having low-capillary lift properties. Preferably, fill material 110is silica sand. Such fill material 110 permits air and contaminants topass up venting well 28 and through screen 32 yet resists upwelling andcondensation of contaminated, liquid, ground water, which are typicallypresent in prior art venting wells perforated at the lower end, andprevents clogging of openings 32 and fouling of vacuum pumps 34, whereemployed. Preferably, the lower portion of venting well 28 additionallycomprises a condensate drain which releases condensate back into thevadose zone rather than accumulating condensate at the bottom of ventingwell 28.

Venting wells 28 may be, but need not be, connected to a fan or vacuumpump 34 via manifold 104. If employed, the fan or vacuum pump 34 ispreferably of a capacity of 10 to 300 cfm. Injection of air viainjection wells 18 volatilizes contaminants and forces thesecontaminants and contaminant-breakdown byproducts up and into ventingwells 28. If employed, the fan or vacuum pump 34 assists in drawing thevolatile contaminants and byproducts into venting wells 28 in acontrolled manner.

In an alternative embodiment of the invention, air injection wells 18,in the absence of extraction wells, are utilized to volatilizecontaminants and provoke biodegradation of contaminants. The volatilizedcontaminants rise to the surface and are vented to the atmosphere.Obviously, this embodiment should not be utilized when control of thevented gases is desired or required.

FIG. 4 illustrates another alternative embodiment of the method andsystem of the present invention. In this embodiment, injection wells 18are constructed as in the preferred embodiment illustrated in FIGS. 1and 3. Venting laterals 106, comprising gas-impermeable piping havingscreens or perforations 108 therein, permit ingress of air,contaminants, and biodegradation byproducts. Venting laterals 106 arebeneath surface 20 far enough to prevent migration of surface water intolaterals 106. Such location eliminates the fouling of venting wells nearthe water table by subsurface water, and fouling of venting pumps bycondensate, associated with previously existing vacuum extraction andventing systems. Venting laterals 106 additionally comprise conduits 112leading to surface 20. Optionally, venting fans or vacuum pumps 34 arefluidly connected to one or more conduits 112.

As illustrated in FIG. 4, the alternative method and system of theinvention may optionally comprise venting chimneys 114 beneath one ormore lateral screens 108. Venting chimneys 114, preferably shafts filledwith silica sand (or other gas-permeable, low capillary-lift material),permit upward migration of air, contaminants, and by-products, butdiscourage upward migration of liquid water. Venting chimneys 114 mayadditionally comprise (not shown) PVC piping having one or more screensor openings therein; the vertical piping may connect to venting lateral106 or may connect to a separate venting manifold. As is readilyobservable by those skilled in the art, venting laterals 106 may beemployed without venting chimneys 114 or with any combination of silicasand shafts, vertical PVC piping, or other venting means known in theart, depending on site stratigraphy and other factors. For example, asilica sand venting chimney may have vertical piping extending onlythrough an upper portion of the chimney.

The gas-impermeable piping 24 and 30 of the injection and venting wells18 and 28 and of venting laterals 106 may consist of metal or plasticpiping, such as one- to two-inch PVC piping. The annulus of all wells(opening between borehole and pipe) is preferably sealed above thescreens (e.g., with a bentonite/cement mixture 116) to prevent suctionloss and migration of surface water and free contaminants to thesubsurface.

Where a liquid contaminant is known to be present as free-product withinthe ground water 14 (or in the soil above the water table), thefollowing method of separation and extraction is employed. FIG. 5illustrates the preferred method and apparatus for free-productextraction. A free-product extractor 50 is inserted in an extendedventing well 28. The extractor 50 comprises a hollow reservoir 52, endcap 54, and an entry cartridge 56. The entry cartridge 56 comprises aprotector 58, outer ports 60, and a filtration screen 62. The filtrationscreen 62 comprises an outer layer 68 and a hydrophobic filter 66. Theentry cartridge 56 covers inner ports 70 permitting passage of fluidcontaminants to the hollow interior 64 of the reservoir 52. Free productextractor may be used in situ or in various configurations for surface,laboratory, or industrial use.

Non-dissolved liquid contaminant is separated from ground water 14 (orextracted from soil above the water table) by placing entry cartridge 56in contact with the contaminant/water mixture (or contaminant/soilmixture) found at the bottom of an extended venting well 28.Alternatively, free-product extraction apparatuses 50 may be placed inbore holes of insertion wells 18, or a combination of insertion wells 18and venting wells 28, or in entirely separate bore holes. Thecontaminant/water mixture contacts filtration screen 62 through outerports 60. Subsurface fluid pressures force liquid contaminant throughfiltration screen 62 into the interior 64. However, water does not enterinterior 64 because it cannot pass through hydrophobic filter 66.Subsurface fluid pressures, and not pumping pressures, force fluidcontaminant to gradually fill reservoir 52. The reservoir 52 then ispumped and allowed to refill before further pumping. This under-pumpingallows the well to retain maximum efficiency.

According to the invention, the following method is employed to extract,analyze, ferment, and reintroduce microorganisms useful inbiodegradation of contaminants. Water or soil samples (or both) aretaken from several contaminated zones (and, at times, fromnon-contaminated zones) within the site, because microbes are notuniformly distributed within a site. The samples are examined todetermine the genera of microbes present and their concentrations.Microbes known or demonstrated to be useful in biodegrading thecontaminant at the site are isolated and fermented to increasepopulation. The site is then inoculated with the heightened populationeither through the point of contamination or through one or moreinjection wells 18 or venting wells 28 (or separate wells).

As the concentration of contaminant decreases, the concentration ofcontaminant degrading microbes must also decrease. If the rate of themicrobial decrease is sufficient that it becomes apparent that the sitewill not reach statutory or desired limits in a rapid fashion, thepreferred embodiment employs the following growth-stimulation method.Using this approach, food supplies (generally organic) or nutrients(generally inorganic) are inserted into the site using the same physicaldistribution of wells as is used for other aspects of this integratedremediation system. This results in a very cost effective enhancement ofthe rate of bioremediation without requiring any additional physicalapparatus. This process takes place primarily in injection wells 18.However, if the vadose zone 12 is exceptionally dry, humidityenhancement and nutrient/food enhancement take place in the ventingwells 28.

The outlets of venting wells 28 or venting laterals 106 may be connectedto suitable stacks, vents, scrubbers, condensers, chemical filtersand/or scavengers (not shown), to collect, dilute or vent contaminantsextracted from the soil and ground water. The preferred embodiment ofthe biotreater uses flow rates in the air injection system which allowmaximum bioremediation of the vapors so that air quality standards arenot exceeded by the fluids vented by the remediation unit. However, somesite conditions are such that one must vent at a heavier or faster rate,thus potentially exceeding air quality standards. Normally the presentinvention is operated in such a fashion that post-treatment of extractedgases is not necessary. However, the present invention provides apost-treatment method which, if necessary on the site, is verycost-effective and requires no electrical power. An example of otheruseful filters are activated carbon filters, prior art biotreaters,treatment by incineration, catalytic oxidation, or ultraviolet rays.These latter techniques are considerably more expensive than is thepresent invention.

The preferred biotreater 80 illustrated in FIGS. 8 through 10 isemployed at the outlets of venting wells 28 or venting laterals 106. Anair conductive pathway (not shown) is established between an outlet anddiffuser 92, passing through inlet 84 into container 82, preferably a55-gallon drum. The biotreater 80 is filled (preferably partiallyfilled) with water impregnated with microbes determined to have adegrading effect on the contaminant being extracted. When the vacuumpump 34 is in operation, contaminated air passes into biotreater 80,bubbles up through the micro-impregnated water from diffuser 92, pastbaffle 90 supported by stand 94, and out through biotreater outlet 86.

A plurality of biotreaters 80 may be connected in series to moreefficiently decontaminate the air extracted by venting wells 28 orventing laterals 106. Biotreaters may be added or deleted from theseries as contaminant concentration from the vacuum pump 34 increases ordecreases. Preferably, the microorganisms placed within the biotreatersare fermented from subsurface samples, and hence are identical to themicroorganisms reintroduced to the subsurface at heightenedconcentration.

When injection occurs via an injection well whose elements, such asliner 24 and screen 26, are confined entirely within the well bore 18,the dispersion into the aquifer 14 of injected substances is somewhatinhibited by the highly localized, almost "point source" character ofthe mode of injection. Such a situation is depicted in FIG. 3. Injectedsubstances, particularly gases, tend to disperse or flow upward andoutward from the bottom of the well, thus forming a zone of injectionflow shaped generally like an inverted cone (with the bottom of the well18 at the cone's apex). It may be desirable, therefore, to implement ameans for increasing the volume of aquifer 14 within the injection flowzone, particularly to include portions of the aquifer very near thedeepest part of the well.

Attention accordingly is invited to FIGS. 11-14, illustrating analternative embodiment of the invention useful for enhancing theefficiency of the injection aspect of the invention. FIG. 11 shows aninjection radius expander, depicted generally at 128, installed withinthe injection well 18 of the FIG. 3 embodiment. Injection radiusexpander 128 is installed within well bore 18 preferably near itsdeepest point. Expander 128 is disposed generally around liner 24,coincidentally or subsequently to the installation of liner 24 itself.The expander 128 serves to provide lateral injection of substancesradially outward from lower portions of a well 128.

The principal components of expander 128 are shown in FIG. 11, andinclude upper slip ring 132, lower attachment ring 134, and at least one(and preferably three to five) radial injection tube 136 with associatedextension brace 138. These principal components are comprised of strong,durable, corrosion-resistant materials, such as stainless steel or thelike. Both slip ring 132 and attachment ring 134 are generally annular,with inside diameters conforming substantially to the outside diameterof well liner 24. Slip ring 132 is not fixed to liner 24, but rather isslidable axially along liner 24. Attachment ring 134, however, issecurely (but perhaps temporarily) attached to the liner 24 so as not tobe slidable along it. Radial injection tube 136 and extension brace 138can be described as rigid rods, although radial injection tube 136 ishollow. Extension brace 138 is hingably connected to upper slip ring 132and also is hingably connected to radial injection tube 136. Radialinjection tube 136 is hingably connected to attachment ring 134. By thissystem of hingable connections, extension brace 138 and radial injectiontube 136 are freely movable, with respect to each other, in the verticalplane containing them.

The operation of expander 128 readily can be understood by analogy tothe operation of a common umbrella. In the analogy, the umbrella isupside-down and minus its canopy. The invention's well liner 24 iscompared to the umbrella handle. Each radial injection tube 136 isanalogized to the rigid ribs of the umbrella which support the umbrellacanopy in its open position. In the "closed" position of thisalternative embodiment, each extension brace 138 and its correspondingconnected radial injection tube 136 are both vertical, with their mutualconnection falling very approximately halfway between slip ring 132 andattachment ring 134 (which rings are maximally separated). The closedposition fosters easy placement of the expander 128 within the confinesof the well 18. Because attachment ring 134 does not slide up or down,as the slip ring 132 is slidably moved down the "handle" or liner 24towards the radial injection tubes 136, the hinge between the extensionbrace 138 moves radially outward, causing the both the brace 138 and thetube 136 also to fold radially outward away from the liner 24, thus"opening" an array of one or more tubes 136, as shown in FIGS. 11, 13and 14.

Once opened up within the aquifer 14, the expander serves to more widelydisperse the injected substances by lengthening the radius of the "cone"of injection flow. In this alternative embodiment, substances arecontinued to be injected down the well 18 for release through screen 26or other perforations in liner 24. But such injection may besupplemented by the injection of substances (typically at high pressureand low volume) through at least one flexible feed tube 130, which isdisposed down the well 18 and leading to the surface. Feed tube 130 isin fluid connection with each radial injection tube 136, such thatsubstances injected down feed tube 130 flow into and are emitted fromthe radial injection tube 136.

FIGS. 12-14 are enlarged views of the expander 128, detailing it majorcomponents and further disclosing its function. FIG. 12 shows theexpander 128 disposed in its closed position around liner 24; FIG. 13shows it in an "open" or extended position.

Attachment ring 134 is fixed to liner 24 in a manner preventingattachment ring from moving up or down liner 24. Attachment ring 134 ishollow or otherwise includes interior passageways in fluid connectionwith feeder tube 130 which has a fitting through the wall of the ring134. Upper slide ring 132, which can slide up or down liner 24, is shownat or near its maximum positional distance from attachment ring 134.

For the sake of illustrative clarity, FIGS. 12 and 13 depict only twosets of radial injection tubes 136,136' and extension braces 138,138';FIG. 14 depicts three sets. It will be understood, however, that theobjects and advantages of this embodiment of the invention may berealized using any number of radial injection tubes 136,136', althoughthree or four, and typically no more than six, are preferred.Description of one radial injection tube 136, and its associatedelements and use, serves to describe them all.

Radial injection tubes 136,136' are rigid hollow tubes. Cylindricaltubes will suffice, but it may be advantageous to utilize tubes with atriangular, oval, or other cross section which fosters movement of tubes136,136' through the material of the aquifer 14. (Sharp edges may alsobe installed on the exterior of a cylindrical tube for the same reason.)Radial injection tubes 136,136' may have openings at their distal ends,or along their lengths, or both, as depicted at orifices 144,144' inFIGS. 12-14.

As shown in FIGS. 12-14, extension rods 138,138' are connected to radialinjection tubes 136,136' by hinges 142,142' Hinges 142,142' permitmovement of rods 138,138' and tubes 136,136' with respect to each otherbut preferably within the geometric plane defined by the rod and tube.Each extension brace 138 similarly is hingably connected to sliding ring132 using hinges disposed radially about sliding ring 132. Proximal endsof radial injection tubes 136,136' likewise are hingably connected aboutthe circumference of attachment ring 134 by means of tube hinges140,140'. Tube hinges 140,140' are a type which permit the hollowinteriors of radial injection tubes 136,136' to remain in continuousfluid communication with the interior passageway of attachment ring 134without regard for the movement of tubes 136,136' with respect toattachment ring 134.

Operation of this alternative embodiment is described with referencefirst to FIG. 12. The expander is disposed within well 18 in the closedposition shown in FIG. 12. After the expander is positioned at thedesired location (with attachment ring 134 suitably affixed to liner24), sleeve pipe 148 is lowered down the well 18 and around liner 24.Sleeve pipe 148 is lowered until it contacts the upper surface of slipring 132, at which time sleeve pipe 148 is forcibly driven downward,preferably hydraulically by means known in the art. As sleeve pipe 148is driven downward, it pushes slip ring 132 ahead of it, which in turncauses all extension rods 138,138' and radial injection tubes 136,136'to pivot in vertical planes radially outward from liner 24, by theaction of hinges 142,142', tube hinges 140,140' and the hingesconnecting rods 138,138' to slip ring 132. Extension rods 138,138' andradial injection tubes 136,136' thus are forced through the surroundingaquifer medium; densely packed aquifer material will require that sleevepipe 148 be hydraulically rammed with comparatively elevated force.Continued downward motion of sleeve pipe 148 results in a continuouslydecreasing angle between extension rods 138,138', until the assemblyobtains the configuration shown in FIGS. 13 and 14. The motionpotentially can continue until radial injection tubes 136,136' havereached a horizontal position; the precise angular positioning of tubes136,136' is controllable through the manipulation of sleeve pipe 148.

With the apparatus configured as depicted in FIGS. 13 and 14, air,oxygen, oxygen-containing substances and the like may be pumped downfeed tube 130. These substances move through feed tube 130 and throughthe interior of attachment ring 134, through tube hinges 140,140', andfinally through the radial injection tubes 136,136'. The substances arethen emitted through the orifices 144,144' in tubes 136,136' forbroadened dispersion into the aquifer. Preferably, substances aresimultaneously injected from the surface through screen 26 via theinterior of liner 24.

FIG. 15 illustrates an alternative embodiment of the expander 128 shownin FIG. 11. This alternative embodiment is identical to the embodimentof FIGS. 12-14, except with respect to the mode of moving slip ring 132downward. In this alternative embodiment, slip ring 132 is verticallypenetrated by at least one threaded hole, through each of which athreaded jack screw 150 is screwed. One (or more) jack screw 150 alsopasses through an unthreaded hole vertically penetrating attachment ring134 and so aligned as to cause the vertical positioning of jack screw150 as shown. Jack screw 150 is free to rotate in the hole throughattachment ring 134, but is fitted with retaining washers or other meansknown in the art for preventing jack screw 150 from moving axiallyupward or downward with respect to attachment ring 134. Accordingly, asshank 152 of jack screw 150 is rotated, by mechanical and/or electricalmeans known in the art, the screwing interaction between jack screw 150and slip ring 132, together with the vertical immobility of jack screw150, causes slip ring 132 to be mechanically drawn toward attachmentring 134, resulting in the "opening" of the radial injection tubes136,136', as previously described. Counter-rotation of the jack screw150 will retract the tubes 136,136' inward, as slip ring 132 is forcedupward by the screwing action.

Although the invention has been described with reference to thesepreferred embodiments, other embodiments can achieve the same results.Variations and modifications of the present invention will be obvious tothose skilled in the art and it is intended to cover in the appendedclaims all such modifications and equivalents. The entire disclosures ofall applications, patents, and publications cited above, and of thecorresponding application are hereby incorporated by reference.

We claim:
 1. An apparatus for laterally dispersing substances outwardfrom an injection well, said apparatus comprising:means for transportingsaid substances vertically downward into said injection well; at leastone injection tube vertically disposable within said injection well andin fluid communication with said means for transporting; and meansmounted vertically above said injection tube for moving said injectiontube radially outward from said injection well.
 2. The apparatus ofclaim 1 wherein said means for transporting comprises a flexible feedertube.
 3. The apparatus of claim 1 wherein said means for transportingcomprises a well liner.
 4. The apparatus of claim 1 wherein said meansfor moving said injection tube radially outward comprises means forpivoting said injection tube outward from said injection well.
 5. Theapparatus of claim 4 wherein said means for pivoting comprises:a rigidmember vertically disposed in said well; and hinge means for connectingsaid injection tube to said rigid member.
 6. The apparatus of claim 5wherein said rigid member comprises a well liner.
 7. The apparatus ofclaim 6 further comprising:a slip ring member slidably disposed aroundsaid rigid member; extension rod means hingably connected to saidinjection tube and hingably connected to said slip ring member; andmeans for vertically sliding said slip ring member along said rigidmember.